The long-term aim if this project is to explore in greater depth, the biology of the steroid-synthesizing cell. There are several areas of uncertainty as to the molecular events involving 1) initiation, propagation, and termination of steroid synthesis, 2) intercompartmental movement of steroid precursors and intermediates, 3) secretion of steroid products. Other areas of uncertainty involve 1) the interaction of subcellular organelles, e.g., mitochondria, endoplasmic reticulum, Golgi apparata, microtubules, microfilaments, lipid droplets, etc., 2) cell-cell interaction or zone-zone interaction (different cells are programmed to secrete predominantly one type of steroid, i.e., glucocorticoid, mineralocorticoid, and sex steroids), 3) life-span and turnover of adrenocortical cells. Current areas of research involve: 1) identification, characterization, and physiology of noncatalytic proteins (membrane bound and/or soluble) of the adrenal cortex that interact with specific steroid ligands; 2) examination of the role of microtubules and contractile proteins in steroid synthesis; 3) identification, characterization and physiology of adrenocortical secretory proteins.